Numerade

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[30 pts] Consider the removal of perchlorate from well water using an SBA exchange resin \( \left.\mathrm{R}-\mathrm{N}^{+}\left(\mathrm{CH}_{3}\right)_{3}\right) \). The following table lists the major anions contained in the well water. Assuming erchlorate is completely removed from the solution, calculate the maximum volume of water that can be treated per liter of resin assuming equilibrium conditions. Assume the total resin capacity f the SBA is \( 1.4 \mathrm{eq} / \mathrm{L} \). \begin{tabular}{|c|c|c|} \hline Parameter & Unit & Value \\ \hline Alkalinity & \( \mathrm{mg} / \mathrm{L} \) as \( \mathrm{CaCo}_{3} \) & 200 \\ \hline Perchlorate & \( \mathrm{mg} / \mathrm{L} \) & 200 \\ \hline Nitrate & \( \mathrm{mg} / \mathrm{L} \) & 9.0 \\ \hline Sulfate & \( \mathrm{mg} / \mathrm{L} \) & 55 \\ \hline \( \mathrm{pH} \) & Unitless & 8.0 \\ \hline \end{tabular} Hints: you need to (1) figure out the concentrations of carbonate and bicarbonate and (2) convert he concentrations to meq/L. You need to (a) check the definition of "alkalinity" and (b) apply pKa o calculate the carbonate anions. Do not forget that some ions contain multiple charges. If some parameters (e.g., the \( \alpha \) value for certrain ions) are not available for your calculation, you need to validate your assumption that can bypass the use of those undavailable parameters.

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INSTANT ANSWER

Which of the following is(are) correct about denitrifiers in the anoxic zone of an MLE process? a. Many denitrifiers are facultative aerobes b. Denitrifiers would compete with phosphate-accumulating organisms for rbCOD if nitrate is present in the anaerobic reactor for EBPR c. N2O is one byproduct generated under certain conditions by denitrifiers, and can be recovered for co-combustion with biogas d. The presence of oxygen can inhibit denitrification process, thus reducing the growth of the denitrifiers.

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Andrew Noble

Numerade educator

n a class of 30 students, 21 have a brother and 14 have a sister. There are 4 students who do not have any siblings. What is the probability that a student has a sister given that they have a brother?

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List 3 advantages for this anoxic/aerobic (MLE) system with internal recycle compared to using an aerobic system only. (b) If the fraction of soluble BOD in the wastewater influent is increased by 30%, what type of bacteria would you expect to be greatly impacted in the system? How would the treatment process be impacted accordingly?

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Breanna Ollech

Numerade educator

For an aerobic heterotrophic bacterium utilizing acetate, how much g of O2 would be needed per g of acetate being consumed?

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Breanna Ollech

Numerade educator

A complete mixed activated sludge process is operated with a clarifier and sludge recycle. The influent soluble BOD concentration is 200 mg/L and the flow is 1000 m3/day. The effluent soluble BOD is 20 mg/L and the effluent VSS concentration is 40 mg/L. What is the oxygen consumption rate of the aeration tank in kg/day? The sludge parameters are as follows: μm = 3 d-1. Ks = 20 mg/L, kd = 0.1d-1, Y = 0.5 g VSS/g BOD

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Your local utility is planning to add a secondary treatment to lower the BOD and suspended solids loading entering an estuary to 10 mg/L BOD5 and 5 mg/L suspended solids. Assume that the suspended solids contribute a BOD5 value equal to 63% of the suspended solids concentration. The plant flow is 14 MGD and effluent from primary treatment contains 240 mg/L BOD5. Assume that the sludge in the primary effluent is negligible, and the secondary clarifier will be capable of producing an effluent with 5 mg/L SS. Use a typical MLVSS:MLSS ratio of 0.7; Assume the following biomass growth and yield parameter Ks= 110 mg/L, Kd = 0.06d^-1, um= 2.0d^-1, Y=0.45 gVSS/ g BOD a) Estimate the operating sludge age required to meet the effluent standards (b) Estimate the required volume of the CSTR aeration basin to maintain a MLVSS of 1800 mg/L. (c) Estimate the F/M entering the aeration basin. (d) Determine the observed cell yield (Yobs) in MLVSS (e) A lab tech measures an SVI of 120 mL/g for the effluent from the aeration basin. Estimate the waste activated sludge flow rate (Qw) necessary to maintain desired sludge age and MLVSS of 1800 mg/L. (f) Calculate the mass of solids (in dry metric tons) that must be processed each year at the plant. (g) Determine RAS

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In the secondary treatment unit of a WWTP, two activated sludge aeration tanks are operated in parallel. Each tank has the following dimensions: 7.0 m wide by 30.0 m long by 4.3 m effective liquid depth. The plant operating parameters are as follows: Flow = 0.0796 m3/s Soluble BOD5 after primary settling = 130 mg/L MLVSS = 1,500 mg/L MLSS = 1.40 x (MLVSS) Settled sludge volume after 30 min = 230.0 mL/L 3Using the following assumptions, determine (a) the solids retention time, (b) the cell wastage flow rate, and (c) the return sludge flow rate for the WWTP. Assume: Allowable BOD in effluent = 25.0 mg/L Suspended solids in effluent = 25.0 mg/L (30% of SS account for BOD) Yield coefficient (Y) = 0.60 mg VSS/mg BOD5 removed Decay rate of microorganisms (kd) = 0.060 d-

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INSTANT ANSWER

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INSTANT ANSWER

determine fs° and Y for one heterotrophic bacterium that grows on glucose oxidation, when NOg is the electron acceptor and the N source, E= 0.6.

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David D.